Daily Archives: November 15, 2014

Estuary Microbial Community Dynamics

Sun Z, Li G, Wang C, Jing Y, Zhu Y, Zhang S, Liu Y. Community dynamics of prokaryotic and eukaryotic microbes in an estuary reservoir. Scientific reports. 2014 Nov 10;4:6966. doi: 10.1038/srep06966.

This study demonstrates both prokaryotic and eukaryotic community structures and dominant taxonomies in different positions of the greatest estuary reservoir for drinking water source in the world in four seasons of one year using 454 pyrosequencing method with total of 312,949 16S rRNA and 374,752 18S rRNA gene fragments, including 1,652 bacteria OTUs and 1,182 fungus OTUs. During winter and spring, the community composition at the phylum level showed that microorganisms had similar structures but their quantities were different. Similarly, obvious changes at the genus level were observed among the samples taken in winter and spring between summer and fall. Microorganisms located the reservoir inlet were founded to be different from those in rear at both phylum and genus level. Air temperature had a stronger effect than sampling location on the microbial community structure. Total nitrogen and dissolved oxygen were algae-monitoring indicators during the whole year. Moreover, Bacillus was an efficient indicator during summer and autumn for bacteria OTUs.

Click here for full paper (fee).

Willingness to Pay for a New Gravity-Driven Membrane Filter, Kenya

Brouwer R, Job FC, van der Kroon B, Johnston R. Comparing Willingness to Pay for Improved Drinking-Water Quality Using Stated Preference Methods in Rural and Urban Kenya. Applied Health Economics and Health Policy. 2014 Nov 8.

BACKGROUND: Access to safe drinking water has been on the global agenda for decades. The key to safe drinking water is found in household water treatment and safe storage systems.

OBJECTIVE: In this study, we assessed rural and urban household demand for a new gravity-driven membrane (GDM)drinking-water filter.

METHODS: A choice experiment (CE) was used to assess the value attached to the characteristics of a new GDM filter before marketing in urban and rural Kenya. The CE was followed by a contingent valuation (CV) question. Differences in willingness to pay (WTP) for the same filter design were tested between methods, as well as urban and rural samples.

RESULTS: The CV follow-up approach produces more conservative and statistically more efficient WTP values than the CE, with only limited indications of anchoring. The effect of the new filter technology on children with diarrhea is among the most important drivers behind choice behavior and WTP in both areas. The urban sample is willing to pay more in absolute terms than the rural sample irrespective of the valuation method. Rural households are more price sensitive, and willing to pay more in relative terms compared with disposable household income.

CONCLUSION: A differentiated marketing strategy across rural and urban areas is expected to increase uptake and diffusion of the new filter technology.

Click here for full paper (fee).

Preventive Strategies Needed for Hepatitis E, India

Kotwal A, Singh H, Verma AK, Gupta RM, Jain S, Sinha S, Joshi RK, Teli P, Khunga V, Bhatnagar A, Ranjan R. A study of Hepatitis A and E virus seropositivity profile amongst young healthy adults in India. Medical journal, Armed Forces India.2014 Jul;70(3):225-9. doi: 10.1016/j.mjafi.2014.06.016.

BACKGROUND: Various Serosurveys and studies provide ample evidence of differing perspectives regarding epidemiology of HAV and HEV in India. This study was conducted to assess the seroprevalence of HAV and HEV and its associated factors with an aim to provide inputs to planners regarding requirement of HAV vaccine.

METHODS: A multi-centric cross sectional survey amongst 4175 healthy trainees (young adults) was carried out in training centres, selected by multistage random sampling, giving equal representation to all regions of India. Sample size was calculated by taking prevalence of HAV seropositivity amongst adults as 60% and alpha 0.05.

RESULTS: Seroprevalence for HAV and HEV was 92.68% (95% CI 91.82, 93.47) and 17.05% (15.90, 18.26), respectively. Logistic regression showed that hand washing without soap, regular close contact with domestic animals, consumption of unpasteurized milk and regular consumption of food outside home were risk factors for HAV (p < 0.05). For HEV, irregular hand washing, consumption of unpasteurized milk and irregular consumption of freshly prepared food were risk factors (p < 0.05).

CONCLUSION: High level of immunity against HAV among the healthy young adults clearly demonstrates that vaccination against HAV is not required at present in our country. The large proportion being susceptible to HEV points towards the requirement of preventive strategies in the form of safe drinking water supply, hygiene, sanitation, increasing awareness and behaviour change with respect to personal hygiene especially hand and food hygiene.

Click here for paper (Open Access).


Exposure to Arsenic in Rice and Seaweed Similar to Drinking Water

Brandon EF, Janssen PJ, de Wit-Bos L. Arsenic: bioaccessibility from seaweed and rice, dietary exposure calculations and risk assessment. Food Additives and Contaminants. Part A, Chemistry, analysis, control, exposure and risk assessment. 2014 Nov 13:1-11.

Arsenic is a metalloid that occurs in food and the environment in different chemical forms. Inorganic arsenic is classified as a class I carcinogen. The inorganic arsenic intake from food and drinking water varies depending on the geographic arsenic background. Non-dietary exposure to arsenic is likely to be of minor importance for the general population within the European Union. In Europe, arsenic in drinking water is on average low, but food products (e.g. rice and seaweed) are imported from all over the world including from regions with naturally high arsenic levels. Therefore, specific populations living in Europe could also have a high exposure to inorganic arsenic due to their consumption pattern. Current risk assessment is based on exposure via drinking water. For a good estimation of the risks of arsenic in food, it is important to investigate if the bioavailability of inorganic arsenic from food is different from drinking water. The present study further explores the issue of European dietary exposure to inorganic arsenic via rice and seaweed and its associated health risks. The bioavailability of inorganic arsenic was measured in in vitro digestion experiments. The data indicate that the bioavailability of inorganic arsenic is similar for rice and seaweed compared with drinking water. The calculated dietary intake for specific European Union populations varied between 0.44 and 4.51 µg kg-1 bw day-1. The margins of exposure between the inorganic intake levels and the BMDL0.5 values as derived by JECFA are low. Decreasing the intake of inorganic arsenic via Hijiki seaweed could be achieved by setting legal limits similar to those set for rice by the Codex Alimentarius Commission in July 2014.

Click here for paper (fee).

“The Moral Case for Fossil Fuels”


I have not read this book yet but the title and this review (here) suggest it presents the proper perspective regarding fossil fuels. Click here for the book.

From Barnes and Noble:

“Could everything we know about fossil fuels be wrong?

For decades, environmentalists have told us that using fossil fuels is a self-destructive addiction that will  destroy our planet. Yet at the same time, by every measure of human well-being, from life expectancy to clean water to climate safety, life has been getting better and better.

How can this be?

The explanation, energy expert Alex Epstein argues in The Moral Case for Fossil Fuels, is that we usually hear only one side of the story. We’re taught to think only of the negatives of fossil fuels, their risks and side effects, but not their positives—their unique ability to provide cheap, reliable energy for a world of seven billion people. And the moral significance of cheap, reliable energy, Epstein argues, is woefully underrated. Energy is our ability to improve every single aspect of life, whether economic or environmental.”